capillary vs catheter

capillary

noun
  • A narrow tube. 

  • Any of the small blood vessels (from 5 to 10 micrometres/micrometers (μm) in diameter) that connect arteries to veins (They are the smallest blood vessels in the body: they convey blood between the arterioles and venules). 

adj
  • Of or pertaining to a narrow tube. 

  • Of, relating to, or caused by surface tension. 

  • Of or pertaining to hair. 

catheter

noun
  • A small tube inserted into a body cavity to administer a drug, create an opening, distend a passageway, or remove fluid. 

How often have the words capillary and catheter occurred in a corpus of books? (source: Google Ngram Viewer )